Association of left ventricular tissue heterogeneity and intramyocardial fat on computed tomography with ventricular arrhythmias in ischemic cardiomyopathy

Usama A Daimee, Eric Sung, Marc Engels, Marc K Halushka, Ronald D Berger, Natalia A Trayanova, Katherine C Wu, Jonathan Chrispin, Usama A Daimee, Eric Sung, Marc Engels, Marc K Halushka, Ronald D Berger, Natalia A Trayanova, Katherine C Wu, Jonathan Chrispin

Abstract

Background: Gray zone, a measure of tissue heterogeneity on late gadolinium enhanced-cardiac magnetic resonance (LGE-CMR) imaging, has been shown to predict ventricular arrhythmias (VAs) in ischemic cardiomyopathy (ICM) patients. However, no studies have described whether left ventricular (LV) tissue heterogeneity and intramyocardial fat mass on contrast-enhanced computed tomography (CE-CT), which provides greater spatial resolution, is useful for assessing the risk of VAs in ICM patients with LV systolic dysfunction and no previous VAs.

Objective: The purpose of this proof-of-concept study was to determine the feasibility of measuring global LV tissue heterogeneity and intramyocardial fat mass by CE-CT for predicting the risk of VAs in ICM patients with LV systolic dysfunction and no previous history of VAs.

Methods: Patients with left ventricular ejection fraction ≤35% and no previous VAs were enrolled in a prospective, observational registry and underwent LGE-CMR. From this cohort, patients with ICM who additionally received CE-CT were included in the present analysis. Gray zone on LGE-CMR was defined as myocardium with signal intensity (SI) > peak SI of healthy myocardium but <50% maximal SI. Tissue heterogeneity on CE-CT was defined as the standard deviation of the Hounsfield unit image gradients (HU/mm) within the myocardium. Intramyocardial fat on CE-CT was identified as regions of image pixels between -180 and -5 HU. The primary outcome was VAs, defined as appropriate implantable cardioverter-defibrillator shock or sudden arrhythmic death.

Results: The study consisted of 47 ICM patients, 13 (27.7%) of whom experienced VA events during mean follow-up of 5.6 ± 3.4 years. Increasing tissue heterogeneity (per HU/mm) was significantly associated with VAs after multivariable adjustment, including for gray zone (odds ratio [OR] 1.22; P = .019). Consistently, patients with tissue heterogeneity values greater than or equal to the median (≥22.2 HU/mm) had >13-fold significantly increased risk of VA events, relative to patients with values lower than the median, after multivariable adjustment that included gray zone (OR 13.13; P = .028). The addition of tissue heterogeneity to gray zone improved prediction of VAs (area under receiver operating characteristic curve increased from 0.815 to 0.876). No association was found between intramyocardial fat mass on CE-CT and VAs (OR 1.00; P = .989).

Conclusion: In ICM patients, CE-CT-derived LV tissue heterogeneity was independently associated with VAs and may represent a novel marker useful for risk stratification.

Keywords: Contrast-enhanced computed tomography; Intramyocardial fat; Ischemic cardiomyopathy; Left ventricular tissue heterogeneity; Ventricular arrhythmia.

© 2022 Heart Rhythm Society. Published by Elsevier Inc.

Figures

Figure 1
Figure 1
Contrast-enhanced computed tomography (CT)-derived left ventricular tissue heterogeneity analysis workflow. Segmentations were performed using a semi-automated approach. Image gradients were calculated across the entire myocardium. Tissue heterogeneity was computed as the standard deviation of the image gradient values across the whole myocardial volume. VA = ventricular arrhythmia.
Figure 2
Figure 2
Histopathology corresponding to LV tissue heterogeneity assessment by contrast-enhanced computed tomography (CE-CT). Top panels: A mild degree of intramyocardial fat and fibrosis infiltrating normal myocardium corresponds with low tissue heterogeneity on CE-CT. Bottom panels: The presence of marked intramyocardial fat and fibrosis infiltrating normal myocardium corresponds with high tissue heterogeneity on CE-CT. HU = Hounsfield unit.

References

    1. Wu K.C. Sudden cardiac death substrate imaged by magnetic resonance imaging: from investigational tool to clinical applications. Circ Cardiovasc Imaging. 2017;10
    1. Roes S.D., Borleffs C.J., van der Geest R.J., et al. Infarct tissue heterogeneity assessed with contrast-enhanced MRI predicts spontaneous ventricular arrhythmia in patients with ischemic cardiomyopathy and implantable cardioverter-defibrillator. Circ Cardiovasc Imaging. 2009;2:183–190.
    1. Estner H.L., Zviman M.M., Herzka D., et al. The critical isthmus sites of ischemic ventricular tachycardia are in zones of tissue heterogeneity, visualized by magnetic resonance imaging. Heart Rhythm. 2011;8:1942–1949.
    1. Piers S.R., Tao Q., de Riva Silva M., et al. CMR–based identification of critical isthmus sites of ischemic and nonischemic ventricular tachycardia. JACC Cardiovasc Imaging. 2014;7:774–784.
    1. Ashikaga H., Sasano T., Dong J., et al. Magnetic resonance–based anatomical analysis of scar-related ventricular tachycardia: implications for catheter ablation. Circ Res. 2007;101:939–947.
    1. Schmidt A., Azevedo C.F., Cheng A., et al. Infarct tissue heterogeneity by MRI identifies enhanced cardiac arrhythmia susceptibility inpatients with left ventricular dysfunction. Circulation. 2007;115:2006–2014.
    1. Venlet J., Tao Q., de Graaf M.A., et al. RV tissue heterogeneity on CT: a novel tool to identify the VT substrate in ARVC. JACC Clin Electrophysiol. 2020;6:1073–1085.
    1. Su L., Siegel J.E., Fishbein M.C. Adipose tissue in myocardial infarction. Cardiovasc Pathol. 2004;13:98–102.
    1. Raney A.R., Saremi F., Kenchaiah S., et al. Multidetector computed tomography shows intramyocardial fat deposition. J Cardiovasc Comput Tomogr. 2008;2:152–163.
    1. Ichikawa Y., Kitagawa K., Chino S., et al. Adipose tissue detected by multislice computed tomography in patients after myocardial infarction. JACC Cardiovasc Imaging. 2009;2:548–555.
    1. Mordi I., Radjenovic A., Stanton T., et al. Prevalence and prognostic significance of lipomatous metaplasia in patients with prior myocardial infarction. JACC Cardiovasc Imaging. 2015;8:1111–1112.
    1. Sasaki T., Calkins H., Miller C.F., et al. New insight into scar-related ventricular tachycardia circuits in ischemic cardiomyopathy: fat deposition after myocardial infarction on computed tomography—a pilot study. Heart Rhythm. 2015;12:1508–1518.
    1. Sung E., Prakosa A., Aronis K.N., et al. Personalized digital-heart technology for ventricular tachycardia ablation targeting in hearts with infiltrating adiposity. Circ Arrhythm Electrophysiol. 2020;13
    1. Cheniti G., Sridi S., Sacher F., et al. Post–myocardial infarction scar with fat deposition shows specific electrophysiological properties and worse outcome after ventricular tachycardia ablation. J Am Heart Assoc. 2019;8
    1. Wu K.C., Wongvibulsin S., Tao S., et al. Baseline and dynamic risk predictors of appropriate implantable cardioverter defibrillator therapy. J Am Heart Assoc. 2020;9
    1. Cheng A., Zhang Y., Blasco-Colmenares E., et al. Protein biomarkers identify patients unlikely to benefit from primary prevention implantable cardioverter defibrillators: findings from the Prospective Observational Study of Implantable Cardioverter Defibrillators (PROSE-ICD) Circ Arrhythm Electrophysiol. 2014;7:1084–1091.
    1. Okada D.R., Miller J., Chrispin J., et al. Substrate spatial complexity analysis for the prediction of ventricular arrhythmias in patients with ischemic cardiomyopathy. Circ Arrhythm Electrophysiol. 2020;13
    1. Moss A.J., Schuger C., Beck C.A., et al. Reduction in inappropriate therapy and mortality through ICD programming. N Engl J Med. 2012;367:2275–2283.
    1. Sánchez-Somonte P., Quinto L., et al. Scar channels in cardiac magnetic resonance to predict appropriate therapies in primary prevention. Heart Rhythm. 2021;18:1336–1343.

Source: PubMed

スポンサーと協力者

医学的状態

薬物療法

3
購読する